It is important especially inside factory buildings that the sound-absorbing elements are cleaned and disinfected at regular intervals.
German Offenlegungsschrift No. 3,048,214 discloses a suspension of sound-absorbing mats with a drain at the lower edge of the mats. The drain catches the wash water when the sound-absorbing elements are cleaned by way of a spraying thereon of detergent from stationary spray nozzles placed next to each mat.
German Offenlegungsschrift No. 4,220,492 discloses sound-attenuating plates to be suspended in large rooms or buildings. Each plate comprises a core of sound-absorbing fibre material covered on the outer side of a porous lining. The plate elements are suspended in slides by means of hooks, and these slides can be displaced along a T-shaped rail. The slide and the T-shaped rail are, however, subjected to some friction.